Radiological Analysis of 300 Consecutive Spine Reconstructions using Cortical Bone Trajectory (CBT) Screws—Comparison between Original and Modified CBT Techniques

Presented at SMISS Annual Forum 2016
By Katsuhisa Fujita
With Yoshihisa Kotani MD, PhD, Takuma Kaibara , Yusuke Kameda , Hideaki Fukaya ,

Disclosures: Katsuhisa Fujita None Yoshihisa Kotani MD, PhD B; L&K Biomed. , Takuma Kaibara None, Yusuke Kameda None, Hideaki Fukaya None,


Cortical Bone Trajectory (CBT) is a novel instrumentation technique recently gaining popularity. Original CBT (oCBT) reached at the posterior column of vertebral body, thus compromising anterior load-sharing. We have modified CBT technique to utilize longer and larger diameter screws for better anchor strength and have reported excellent clinical outcomes previously. 


Radiologically compare the clinical results of 260 cases of modified CBT (mCBT) versus 40 cases of original CBT (oCBT) reconstructions. 


260 mCBT cases (mean age 71y.o.) and 40 oCBT cases (mean age 70.4y.o.) were included. Spinal disorders included degenerative spine disease, deformity, osteoporotic collapse, trauma and infection. Surgery included MIS-PLF, MIS-TLIF, MIDLF and deformity correction with various MIS techniques. Outcomes were assessed with screw loosening (SL), screw breakage (SB), fusion rate (FR) and revision rate (RR). 


Mean number of segments fixed per case was 2.2 in mCBT and 1.3 in oCBT. Overall, 1393 mCBTs and 174 oCBTs were inserted. There were 12 cases of mCBT SL (4.6%) and 4 cases of oCBT SL (10.0%). There were no SB in mCBT (0%) and 3 cases of SB in oCBT (7.5%). There were 11 cases of pseudarthroses in mCBT (FR 96%) and 1 case in oCBT (FR 97%). There were 16 cases of revision in mCBT (RR 6.2%) and 2 cases in oCBT (RR 5.0%). There was no significant difference between two groups in terms of SL, FR and RR, however, the significant difference was demonstrated between two groups in SB.


We have started original CBT for superior stability and less invasiveness for osteoporotic spinal reconstructions since 2012. Our further experiences allowed us to improve the anterior column support, anchoring strength and construct stability by utilizing larger and longer screws through different trajectory of mCBT. The mCBTs effectively prevented screw breakage and allowed superior cortical bone contact to withstand pullout forces and leverage. This analysis is not matched case-control study, however, our mCBT technique is an effective option for osteoporotic spinal reconstruction.